This invention generally relates to sugar kinases and specifically to novel anomeric D/L sugar kinases with expanded substrate specificity and methods of use.
Many clinically important medicines are derived from glycosylated natural products, the D- or L-sugar substituents of which often dictate their overall biological activity. This paradigm is found throughout the anticancer and antiinfective arenas with representative clinical examples (FIG. 1a) including enediynes (calicheamicin, 1), polyketides (doxorubicin, 2; erythromycin, 3), indolocarbazoles (staurosporine, 4), non-ribosomal peptides (vancomycin, 5), polyenes (nystatin, 6), coumarins (novobiocin, 7), or cardiac glycosides (digitoxin, 8). Given the importance of the sugars attached to these and other biologically significant metabolites, extensive effort has been directed in recent years toward altering sugars as a means to enhance or alter natural product-based therapeutics by both in vivo and in vitro approaches. Among these, in vitro glycorandomization (IVG) makes use of the inherent or engineered substrate promiscuity of nucleotidylyltransferases and glycosyltransferases to activate and attach chemically synthesized sugar precursors to various natural product scaffolds. This efficiently incorporates highly functionalized “unnatural” sugar substitutions into the corresponding natural product scaffold (FIG. 1b).
Accordingly, the need remains for natural and/or engineered enzymes that are promiscuous in their substrate specificity and capable of increased catalytic activity to enhance multiplicity of available glycosylated natural compounds.